A histopathological study of injured spinal cord and peripheral nerve will be carried out using histological, histochemical and immunohistochemical methods. Investigations will be performed on hibernating, nonhibernating, and neonatal mammals. The reaction of nervous tissues to different kinds of injury will be investigated. Experiments will be done to clarify the relationship of axonal transport mechanisms and of neuronotrophic influences to axonal regeneration in the central and peripheral nervous system.